C Programming

====

This assignment requires you to write functions to produce weather tables. It also uses a do-while loop and nested for loops, along with the math library. Your program will ask the user for inputs, then produce a weather table, repeatedly until the user is finished. Use functions to isolate the logical steps of the task, including the weather calculations themselves. You should also use functions to flush excess input from stdin, and to print standardized lines around your tables. Submit your source file. Remember to include a comment with your name, assignment number and description, and date. Program behavior An example run of the instructor's program is at the bottom of this writeup. Yours doesn't have to look identical, but it should look very similar to this. Your program should use a do-while loop to repeatedly ask for a table choice. The user enters a 'w' for a windchill table, a 'h' for a heat index table, or 'q' to quit the program. Having determined which table to produce, ask for the temperature range (minimum and maximum) in degrees Fahrenheit; these values should be of type float or double. Also get either the wind-speed range (for the windchill table) or the relative-humidity range (for the heat-index table); these values should be integers. Use nested for loops to create a table of perceived temperatures for each combination of temperature and wind or humidity. Whether heat index or windchill, the output table must contain 11 rows and 6 columns. This can be done by computing step sizes of (maximum-temperature - minimum-temperature)/10 for the outer for loop; and (max.-humidity-or-wind - min.-humidity-or-wind)/5 for the inner loop. Heat Index calculation A detailed description of the heat index is available from this NOAA webpage. A regression equation for calculating the heat index is: Heat Index = -42.379 + (2.04901523 × Temp ) + (10.14333127 × RH ) - (0.22475541 × Temp × RH ) - (0.00683783 × Temp 2 ) - (0.05481717 × RH 2 ) + (0.00122874 × Temp 2 × RH ) + (0.00085282 × Temp × RH 2 ) - (0.00000199 × Temp 2 × RH 2 ) This formula is considered valid for heat-index values above 80 degrees F, with an error of ±1.3 degrees F. You can use the pow() function to calculate the squares (2nd power) of Temp and RH. pow() is available in the header file. You will also need to link in the math library by using the -lm flag, like this: gcc -Wall -o myprog myprog.c -lm Another way to write the heat index expression is to use exponential notation for the constants, like this:

Heat Index = -42.379 + (2.04901523 × Temp ) + (10.14333127 × RH ) - (0.22475541 × Temp × RH ) - (6.83783e-3 × Temp 2 ) - (5.481717e-2 × RH 2 ) + (1.22874e-3 × Temp 2 × RH ) + (8.5282e-4 × Temp × RH 2 ) - (1.99e-6 × Temp 2 × RH 2 ) Exponential notation is useful for very large and very small numbers, and C is happy with it. Wind Chill calculation A detailed description of wind chill is available from this NOAA webpage. The formula for calculating wind chill is:

WindChill = 35.74 + (0.6215 × Temp ) - (35.75 × Wind 0.16 ) + (0.4275 × Temp × Wind 0.16 ) The windchill calculation is considered valid for wind speeds between 3 mph and 60 mph, and temperatures between -45 degrees F and +45 degrees F. Note that you must take a non-integer power of the wind speed. To do this, you need the pow() function, available in the header file. You will also need to link in the math library by using the -lm flag, like this: gcc -Wall -o myprog myprog.c -lm Example run 507] ./weather-tables heat index, wind chill, or quit? w w... temperature range: -10 30 windspeed range: 4 25 T \ W 4.0 8.2 12.4 16.6 20.8 25.0 ----- ----- ----- ----- ----- ----- ----- -10.0 -20.4 -26.3 -30.0 -32.8 -35.1 -37.0 -6.0 -15.8 -21.4 -25.0 -27.7 -29.9 -31.7 -2.0 -11.2 -16.6 -20.0 -22.5 -24.6 -26.4 2.0 -6.6 -11.7 -14.9 -17.4 -19.4 -21.0 6.0 -2.0 -6.8 -9.9 -12.2 -14.1 -15.7 10.0 2.7 -1.9 -4.9 -7.1 -8.9 -10.4 14.0 7.3 2.9 0.1 -1.9 -3.6 -5.1 18.0 11.9 7.8 5.2 3.2 1.6 0.3 22.0 16.5 12.7 10.2 8.4 6.9 5.6 26.0 21.1 17.5 15.2 13.5 12.1 10.9 30.0 25.8 22.4 20.3 18.7 17.4 16.3 ----- ----- ----- ----- ----- ----- ----- heat index, wind chill, or quit? x x... Unrecognized choice heat index, wind chill, or quit? h h... temperature range: 80 110 humidity range: 60 95 T \ H 60.0 67.0 74.0 81.0 88.0 95.0 ----- ----- ----- ----- ----- ----- ----- 80.0 81.8 82.6 83.4 84.4 85.3 86.4 83.0 85.9 87.6 89.5 91.6 94.0 96.5 86.0 91.1 93.8 96.9 100.3 104.1 108.3 89.0 97.4 101.2 105.6 110.4 115.8 121.8 92.0 104.7 109.8 115.6 122.0 129.1 136.9 95.0 113.1 119.6 126.9 135.0 143.9 153.6 98.0 122.6 130.6 139.5 149.4 160.3 172.0 101.0 133.1 142.8 153.5 165.3 178.2 192.1 104.0 144.8 156.2 168.8 182.6 197.6 213.8 107.0 157.5 170.7 185.3 201.3 218.6 237.2 110.0 171.2 186.5 203.3 221.5 241.1 262.2 ----- ----- ----- ----- ----- ----- ----- heat index, wind chill, or quit? q